1. Field of the Invention
The present invention relates to a ratchet buckle assembly for tightening a strap for binding a load in a desired position in safely.
2. Description of tile Prior Art
In a conventional ratchet buckle assembly for tightening a strap, as disclosed in U.S. Pat. No. 4185360, a main body and a handle are separately constructed, and combined with each other together with a winding shaft, cross bars, grips and like components. Further provided in the conventional ratchet buckle assembly is a safety projections. In the conventional assembly, such projection is formed in a lower portion of the handle, and brought into contact with a notch portion of a ratchet so that the ratchet is fixedly engaged with each of opposite ratchet wheels to prevent the winding shaft from being reversely rotated in a condition in which the handle is in its eventually-locked up position. When the strap is loosed, a ratchet drive lever of the conventional assembly is pulled to have the handle rotated through an angle of approximately 180.degree.. An end portion of the ratchet drive lever is bent at right angles to the remaining portion so as to form a grip of the lever. A spring means of the ratchet drive lever of the conventional assembly is constructed of a coil spring.
However, in the conventional ratchet buckle assembly having the above construction, in spite of the presence of a considerable load to which each of the main body and the handle is subjected, the conventional assembly is poor in mechanical strength since each of the main body and the handle of the conventional assembly has its arms formed independently of each other. Further, in the conventional assembly, since the ratchet is provided with the notch, the ratchet is poor in mechanical strength relative to each of the corresponding ratchet wheels for statically holding the load.
In addition, in the conventional assembly, the ratchet drive lever is poor in operability, particularly in a condition in which a large load is applied since a grip of the lever is too small in size. Further, in the conventional assembly, since the coil spring is used, it is hard for the ratchet drive lever to slidably move in a direction perpendicular to a longitudinal axis of the winding shaft, which makes it difficult to uniformly apply a load to the opposite ratchet wheels.